Inserting some values in XML DOM

XML Document object model(DOM) class is a representation of the xml document in memory,

The DOM class lets you read, write , manipulate the xmldocument.

The below examlple for reading and writing xml in file using xmldocument objects.

string getvalueexisting = string.Empty;
string getvaluetag = string.Empty;
string s = string.Empty;
string firstname = txtfirstname.Text;
string lastname = txtlastname.Text;
string address = txtaddress.Text;
string path = Server.MapPath("XMLDATA");
XmlDocument copyexisting = new XmlDocument();
copyexisting.Load(path + "\\test.xml");
XmlTextReader XTR = new XmlTextReader(path + "\\test.xml");
while (XTR.Read())
{
if (XTR.Name != "student")
{
if (XTR.NodeType == XmlNodeType.Element)
{
getvalueexisting += "<" + XTR.Name + ">";
}
if (XTR.NodeType == XmlNodeType.Text)
{
getvalueexisting += XTR.Value;
}
if (XTR.NodeType == XmlNodeType.EndElement)
{
getvalueexisting += "</" + XTR.Name + ">";
}
}
}
XTR.Close();
s = "<student>" + getvalueexisting + "<abc><firstname>" + firstname + "</firstname><lastname>" + lastname + "</lastname><address>" + address + "</address></abc></student>";
xmldoc.LoadXml(s);
xmldoc.Save(path + "\\test.xml");